1. Field
The present disclosure relates to digital document production equipment and, more specifically, to the enhancement of binary images stored in digital document production equipment.
2. Description of Related Art
Digital document production equipment is very common in today's office environment. Generally, such equipment, which includes printers, copiers, facsimiles, and other multifunction (MF) machines, is configured to capture text and images as digital image data and either reproduce the captured text and images on media based on the digital image data or format the digital image data in a manner suitable for transport across a network.
By way of example, consider the case of MF machines having digital copying capabilities, where original documents bearing images to be reproduced on paper sheets are typically loaded into the tray of a document handler. The documents are drawn one sheet at a time and moved relative to an image sensor that records reflected light from a series of small areas in the original image as the image moves past the sensor to yield a set of digital signals.
The digital signals are subsequently converted into binary image data. The binary image data is then compressed and stored in memory and, upon printing, the stored compressed binary image data is read out of memory, decompressed, and forwarded to an output device, such as, for example, an image output terminal (IOT) to print the scanned image on a sheet.
With regard to the quality of the reproduced image itself, some MF machines include user-selectable image enhancement options that are applied to the continuous tone image prior to binarization. Such continuous tone image formats are of higher resolution and typically comprise 8-bits (or higher) per pixel that represent greyscale or color images in the form of continuously varying tonal ranges. The user-selected enhancement options adjust image features and artifacts by manipulating and/or transforming the continuous tone image data. The enhanced continuous tone image data is then typically binarized and then supplied to the IOT. This results in an output image that has higher image quality and/or that has the user-selected image enhancement options applied to the input/scanned image.
More sophisticated MF machines offer a “store and retrieve” option, whereby stored image data may be later accessed and retrieved for future and different usage as originally intended. Upon selection of this option, the image data is stored in memory and may include the user-selected image enhancement options' information (i.e., image metadata). However, as a practical matter, because memory storage space remains at a premium and processing speed is an important factor, the image data is stored in the compressed binary image data format—rather than the continuous tone image formats. As a result, upon retrieval, new image adjustments and enhancements effected by the user-selectable options cannot be applied. Because binary image data is limited in its ability to accommodate image enhancements and improvements, the use of the “store and retrieve” feature becomes limited. For example it may force users to either re-copy the original image or settle for lower fidelity reproductions of the previously stored image.